ISSN 2736-1756
Advanced Journal of Microbiology Research ISSN 2241-9837 Vol. 13 (3), pp. 001-007, March, 2019. © International Scholars Journals
Full Length Research Paper
Determination of insecticidal toxicity of three species of entomopathogenic spore -forming bacterial isolates against Tenebrio molitor L. (Coleoptera: Tenebrionidae)
N. Du Rand and M. D. Laing
Department of Plant Pathology, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg, Republic of South Africa.
Accepted 10 January, 2019
Abstract
Bioassays were conducted using larvae of mealworms, Tenebrio molitor, to determine lethal concentration for five entomopathogenic strains of spore-forming bacteria. Lethal concentration was determined by feeding T. molitor larvae cabbage discs dipped in whole cell cultures of these five strains of bacteria. The strains of bacteria were isolates of Bacillus cereus, Bacillus thuringiensis and Brevibacillus laterosporus. An isolate of B. cereus required the highest concentration of viable spores (8.531 x 107 spores ml-1) to achieve its LC50, whereas an isolate of B. laterosporus required the lowest concentration of viable spores (3.388 x 106 spores ml-1) to achieve LC50.
Key words: Mealworms, spore-forming bacteria, bioassays.